[sdiy] "Tube screamer" style distortion, with voltage-controllable drive, via a vactrol

[Antti Huovilainen]

On Mon, 3 May 2010, David G. Dixon wrote:

> When the square wave was being fed, the output looked like a HPF 
> response (differentiation).  Does that mean that there are caps in the 
> signal line?

Yes and no. Tube screamer uses basic non-inverting gain stage with 
DC blocker limiting the gain to 1 at DC and diode clipper in the feedback 
path. It's perhaps easiest to think of it as inverting opamp gain stage 
with highpass and diode clipper inverted (to bring polarity back to 
original) and mixed with the original signal.

Antti

"No boom today. Boom tomorrow. There's always a boom tomorrow"
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